These are mysteries with historical and cultural content. Mortensen is a fun and good-natured hero who trots the globe and travels throughout history. Educational back matter offers the readers more information on the topics covered.

Mortensen must transport the Red Ruby from New York City in 1937 to Versailles, France, in 1993. That would be a simple job for a time traveler, but he's not the only one with plans for the gem. A gun moll, a fortune teller, a gangster, an aristocrat, and two henchmen are hot on his trail. Mortensen's mad chase will lead him from Denmark to Burma, and even to the deck of the Titanic!